/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:		arm_sub_f32.c
*
* Description:	Floating-point vector subtraction.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMath
 */

/**
 * @defgroup BasicSub Vector Subtraction
 *
 * Element-by-element subtraction of two vectors.
 *
 * <pre>
 *     pDst[n] = pSrcA[n] - pSrcB[n],   0 <= n < blockSize.
 * </pre>
 *
 * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
 */

/**
 * @addtogroup BasicSub
 * @{
 */


/**
 * @brief Floating-point vector subtraction.
 * @param[in]       *pSrcA points to the first input vector
 * @param[in]       *pSrcB points to the second input vector
 * @param[out]      *pDst points to the output vector
 * @param[in]       blockSize number of samples in each vector
 * @return none.
 */

void arm_sub_f32(
    float32_t *pSrcA,
    float32_t *pSrcB,
    float32_t *pDst,
    uint32_t blockSize)
{
    uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    float32_t inA1, inA2, inA3, inA4;              /* temporary variables */
    float32_t inB1, inB2, inB3, inB4;              /* temporary variables */

    /*loop Unrolling */
    blkCnt = blockSize >> 2u;

    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
     ** a second loop below computes the remaining 1 to 3 samples. */
    while(blkCnt > 0u)
    {
        /* C = A - B */
        /* Subtract and then store the results in the destination buffer. */
        /* Read 4 input samples from sourceA and sourceB */
        inA1 = *pSrcA;
        inB1 = *pSrcB;
        inA2 = *(pSrcA + 1);
        inB2 = *(pSrcB + 1);
        inA3 = *(pSrcA + 2);
        inB3 = *(pSrcB + 2);
        inA4 = *(pSrcA + 3);
        inB4 = *(pSrcB + 3);

        /* dst = srcA - srcB */
        /* subtract and store the result */
        *pDst = inA1 - inB1;
        *(pDst + 1) = inA2 - inB2;
        *(pDst + 2) = inA3 - inB3;
        *(pDst + 3) = inA4 - inB4;


        /* Update pointers to process next sampels */
        pSrcA += 4u;
        pSrcB += 4u;
        pDst += 4u;

        /* Decrement the loop counter */
        blkCnt--;
    }

    /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
     ** No loop unrolling is used. */
    blkCnt = blockSize % 0x4u;

#else

    /* Run the below code for Cortex-M0 */

    /* Initialize blkCnt with number of samples */
    blkCnt = blockSize;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    while(blkCnt > 0u)
    {
        /* C = A - B */
        /* Subtract and then store the results in the destination buffer. */
        *pDst++ = (*pSrcA++) - (*pSrcB++);

        /* Decrement the loop counter */
        blkCnt--;
    }
}

/**
 * @} end of BasicSub group
 */
